1. Field of the Invention
The invention relates to a female terminal fitting with a resilient contact.
2. Description of the Related Art
A known female terminal fitting with a resilient contact is disclosed in U.S. Pat. No. 5,235,743 and is illustrated in FIG. 7 herein. With reference to FIG. 7, a female terminal fitting 1 is used with a male terminal fitting 2 that has a tab 3 at one end. The female terminal fitting 1 has a rectangular tubular main body 4 with a bottom wall 5. A resilient contact piece 6 is folded back into the tubular main body 4 and is formed into a triangular shape with a contact 7 at the vertex of the triangle. A base 8 projects forward from the bottom wall 5 and a U-shaped fold 9 extends between the base 8 and the resilient contact 6. The tab 3 of the male terminal fitting 2 can be inserted into the tubular main body 4 of the female terminal fitting 1. Thus, the tab 3 presses the contact 7 down and deforms the resilient contact piece 6 about the fold 9 as a deformation supporting point.
The terminal fittings 1, 2 can be miniaturized by reducing the width and length of the tab 3 of the male terminal fitting 2. However, the contact 7 of the resilient contact piece 6 of the female terminal fitting 1 must be moved forward to a position that conforms to the dimensions of the shorter tab 3. These dimensional changes of the resilient contact piece 6 necessarily reduce the distance between the contact 7 and the fold 9. Thus, the fold 9 cannot be deformed as easily and an insertion resistance of the tab 3 becomes larger.
The invention was developed in view of the above problem and an object thereof is to enable a resilient contact piece to be deformed easily.
The invention is a female terminal fitting with a base wall and a resilient contact piece that projects from a leading end of the base wall. The resilient contact piece has a contact for contacting a mating male terminal fitting. The mating male terminal fitting presses the contact and hence the resilient contact piece is deformed with a fold thereof as a support point. The resilient contact piece has at least one rigidity-lowering portion between the base of the resilient contact piece and the contact. The rigidity-lowering portion has a smaller cross-sectional area with respect to a direction at an angle to the longitudinal direction.
The resilient contact piece preferably is folded back and substantially faces the base wall.
Preferably, the resilient contact piece is supported only at one end.
The at least one rigidity-lowering portion may be provided along an area of the resilient contact piece that includes the fold.
The mating male terminal fitting contacts the contact of the resilient contact piece. Thus, the resilient contact piece deforms resiliently with the fold as a supporting point. The resilient contact piece has the rigidity-lowering portion with a smaller cross-sectional area. Accordingly the rigidity of the resilient contact piece is reduced, and the resilient contact piece can be deformed easily.
Miniaturized male and female terminal fittings require the contact of the female terminal fitting to be closer to the fold and, therefore, the resilient contact piece tends to be difficult to deform. The present invention is particularly suitable for such smaller female terminal fittings.
The rigidity-lowering portion preferably is spaced from the fold on the resilient contact piece. Thus, the concentration of stress on the fold during the resilient deformation of the resilient contact piece is alleviated.
The resilient contact piece is formed into a substantially triangular or pointed shape. More particularly, the resilient contact piece extends at an angle from the contact toward the side opposite from the fold and has an extending end that contacts the base wall as the resilient contact piece is deformed beyond a specified degree. The rigidity-lowering portion of the resilient contact piece is spaced from the fold and the contact. Additionally, an auxiliary rigidity-lowering portion may be provided on the resilient contact piece at a position spaced between the contact and the extending end. The auxiliary rigidity-lowering portion has a smaller cross-sectional area with respect to a direction at an angle to the longitudinal direction.
The mating male terminal fitting presses the contact and causes the resilient contact piece to deform with the fold as a support point. Sufficient deformation about the fold brings the extending end into contact with the base wall. The resilient contact piece then is deformed with the extending end as a support point. The auxiliary rigidity-lowering portion and the rigidity-lowering portion enable the resilient contact piece to be deformed easily despite an increased resilient force due to the contact of the extending end with the bottom wall.
The rigidity-lowering portion and the auxiliary rigidity-lowering portion are provided at the positions away from the fold and the contact. Thus, the concentration of stress on the fold and the contact during the resilient deformation of the resilient contact piece can be alleviated.
The auxiliary rigidity-lowering portion is spaced from the extending end. As a result, a sufficient width can be ensured for the extending end to contact the base wall. Thus, the resilient contact piece can be supported to incline about its longitudinal axis during the resilient deformation and a contact state with the mating male terminal fitting can be stabilized.
The rigidity-lowering portion preferably has one or more cut-away portions formed by cutting away opposite edges of the resilient contact piece. The cut-away portions preferably are formed in a portion of the resilient contact piece excluding the area of the contact.
The rigidity-lowering portion may comprise one or more narrowed portions formed at an edge of the projecting base.
The base wall preferably has at least one excessive deformation preventing portion to avoid an excessive deformation of the resilient contact piece.
The projecting base of the base wall preferably is separated from the adjacent wall(s) by means of at least one slit.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.